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    IdahoFredd2020's Avatar
    IdahoFredd2020 Posts: 1, Reputation: 1
    New Member

    Sep 7, 2020, 01:26 PM
    Leaking Lead joint
    I have a leaky cast iron joint. Not a big one but it is frequently dripping. I will add a picture when I get it figured out.

    This is in the basement. Above this is a toilet. It flushes down into that pipe which then goes into that wye/tee which is the vent drain pipe.

    Initially I thought it was from the wax seal under the toilet. When I looked up at the pipes the area under the toilet was dry but I could see that there was moisture from joint at the wye/tee. It is over a cabinet/shelf. It was dripping on it and then running off the edge on to the washing machine.

    The pipes are pretty dry inside right now. The toilet that drains into them has not been used for many months. I was told before doing any repairs to see if there was any obstructions that would cause the waste water to back up. I removed the toilet and stuck a homemade probe/scope down the drain. I think it went as far as the wye/tee but it didn’t seem to go downward. I then went up on the room and sent it down the vent opening. I went down 16-18 feet quickly and easily so I am pretty sure there are no obstructions to a little past the wye/tee. What I don’t understand is why is looks “wet” when nothing has been draining down it? It has been easily 3 or 4 months since it has been used. The bowl is dry and so is the trap.

    I have been to two different Home Depots, two different Lowe’s and a plumbing supply/contractor. They all said to use a silicone product. I went to one other plumbing supply/contractor and they loaned me some caulking tools and said to beat it back in. I guess I will try that first.

    Any other suggestions? What if it doesn’t work? Silicone? This does not seem to be a simple DIY and most of the people I talked to were unfamiliar with this type of problem.
    massplumber2008's Avatar
    massplumber2008 Posts: 12,832, Reputation: 1212
    Senior Plumbing Expert

    Sep 8, 2020, 07:05 AM
    Hi Fred

    You can try "beating" the lead back in but if you hit the hub too hard you can crack the fitting and then your problems grow exponentially!!

    Instead, take a good steel wire brush and clean up the lead area where the pipe is leaking. Take that brush and also clean the rest of the lead joint well. Then, purchase a TWO-PART EPOXY PUTTY stick from a local home supply store. Take the putty and mix the two parts until a uniform color/consistency and then apply that to the lead joint all around the joint. Push the putty into the joint and leave a hump of putty all around the joint. Next, take a little water and smooth the putty out between the cast iron hub and the cast iron pipe being sure to visually see that the edges are smoothed out for best end result. Work quickly...epoxy putty dries pretty fast. Let it dry and hopefully that fixes the issue for many years to come.

    Good luck!


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